Overcurrent protection anti-sensitive circuit

Abstract

The utility model provides an over-current protection anti-sensitive circuit, comprising a breaker QF, the breaker QF is respectively connected with a relay KA, a time-delay relay KT and a load L, the relay KA is also connected with a diode RD and the time-delay relay KT, and the diode RD is also connected with the time-delay relay KT; through a group of normally open contacts of a relay KA and two groups of normally closed contacts of a time-delay relay KT, a circuit breaker QF can be effectively connected into a circuit, a circuit overcurrent protection effect is achieved, meanwhile, full-process full-power operation of a load L can be guaranteed, and the circuit is simple in structure and low in cost.

Description

Technical Field

[0001] The utility model belongs to the technical field of industrial control, and in particular relates to an overcurrent protection anti-sensitivity circuit. Background Art

[0002] The existing overcurrent protection technology is to connect a controllable circuit protection device with a larger current protection value to the front end of the load, or to connect a current limiting resistor in series in the circuit. The disadvantages of these two overcurrent protection technologies are:

[0003] 1. Failure to accurately and effectively set the load current protection value may easily cause load damage;

[0004] 2. The load cannot run at full power throughout the entire process. Utility Model Content

[0005] In order to solve the above technical problems, the utility model provides an overcurrent protection anti-sensitivity circuit.

[0006] The utility model is realized through the following technical solutions.

[0007] An overcurrent protection anti-sensitive circuit comprises a circuit breaker QF, wherein the circuit breaker QF is respectively connected to a relay KA, a time delay relay KT and a load L, the relay KA is further connected to a diode RD and the time delay relay KT, and the diode RD is further connected to the time delay relay KT.

[0008] The power input end of the circuit breaker QF is connected to the positive electrode of the VCC power supply and the moving contacts of a group of normally open contacts of the relay KA, the power output end is connected to the static contacts of a group of normally open contacts of the relay KA and one end of the load L, one end of the control end is connected to one end of the control end of the delay relay KT and the second control signal, and the other end of the control end is connected to the negative electrode of the VCC power supply after being connected to the other end of the control end of the delay relay KT and the other end of the load L.

[0009] One end of the control end of the relay KA is connected to the cathode of the diode RD and the first control signal, and the other end of the control end is connected to the moving contacts of the two groups of normally closed contacts of the delay relay KT and the anode of the diode RD.

[0010] The static contacts of the two groups of normally closed contacts of the time delay relay KT are connected to the load L and then connected to the negative electrode of the VCC power supply.

[0011] The relay KA is an intermediate relay.

[0012] The time delay relay KT is an intermediate relay.

[0013] The beneficial effects of the utility model are as follows: through a group of normally open contacts of a relay KA and two groups of normally closed contacts of a delay relay KT, the circuit breaker QF is effectively connected to the circuit to play a role in circuit overcurrent protection, while ensuring that the load L operates at full power throughout the entire process, and the circuit structure is simple and the cost is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a circuit schematic diagram of the utility model. DETAILED DESCRIPTION

[0015] The technical solution of the utility model is further described below, but the scope of protection required is not limited to the description.

[0016] like Figure 1 As shown, an overcurrent protection anti-sensitive circuit includes a circuit breaker QF, wherein the circuit breaker QF is respectively connected to a relay KA, a time delay relay KT and a load L, wherein the relay KA is also connected to a diode RD and the time delay relay KT, and the diode RD is also connected to the time delay relay KT.

[0017] The power input end of the circuit breaker QF is connected to the positive electrode of the VCC power supply and the moving contacts of a group of normally open contacts of the relay KA, the power output end is connected to the static contacts of a group of normally open contacts of the relay KA and one end of the load L, one end of the control end is connected to one end of the control end of the delay relay KT and the second control signal, and the other end of the control end is connected to the negative electrode of the VCC power supply after being connected to the other end of the control end of the delay relay KT and the other end of the load L.

[0018] One end of the control end of the relay KA is connected to the cathode of the diode RD and the first control signal, and the other end of the control end is connected to the moving contacts of the two groups of normally closed contacts of the delay relay KT and the anode of the diode RD.

[0019] The static contacts of the two groups of normally closed contacts of the time delay relay KT are connected to the load L and then connected to the negative electrode of the VCC power supply.

[0020] The relay KA is an intermediate relay.

[0021] The time delay relay KT is an intermediate relay;

[0022] Specifically, the use of relay KA and time delay relay KT as intermediate relays can achieve the following technical effects: while the circuit has an overcurrent protection function, the circuit breaker QF will not be affected by the transient current at the moment when the load L is energized.

[0023] Specifically, the working principle of an overcurrent protection anti-sensitive circuit of the utility model is: according to the duration of the pump-up current generated when the load L is powered on, the timing time of the KT delay relay is selected;

[0024] When the first control signal of relay KA is valid, its normally open contact is closed, and the power supply forms a loop from the normally open contact of relay KA to load L, and load L starts to work; at this time, the transient pump-up current generated by the load L at the moment of power-on is carried by the power supply circuit; according to the actual circuit requirements, the second control signal controlled by the delay relay KT and the circuit breaker QF can be made valid after a period of time after the first control signal of relay KA is valid;

[0025] After the second control signal is valid, the delay relay KT starts timing, and at the same time, the main circuit of the circuit breaker QF is connected to the main circuit of the load L, and is connected in parallel with the normally open contact of the relay KA that is normally closed to supply power to the load L; after the timing is over, the normally closed contact of the delay relay KT is disconnected, and at the same time, the normally open contact of the relay KA is disconnected because the first control signal of the relay KA is invalid, and the power supply forms a loop to the load L through the main circuit of the circuit breaker QF, and the circuit breaker QF starts to monitor the working current of the load L; if the working current of the load L reaches the preset current value of the circuit breaker QF, the main circuit of the circuit breaker QF is overloaded and disconnected, the load L stops working, and the second control signal is invalid.

[0026] After the first control signal and the second control signal are validated again in the above order, the circuit function can be restored.

[0027] The beneficial effects of the utility model are as follows: through a group of normally open contacts of a relay KA and two groups of normally closed contacts of a delay relay KT, the circuit breaker QF is effectively connected to the circuit to play a role in circuit overcurrent protection, while ensuring that the load L operates at full power throughout the entire process, and the circuit structure is simple and the cost is low.

Claims

1. An overcurrent protection anti-sensitivity circuit, characterized in that: It includes a circuit breaker QF, the circuit breaker QF is connected to the relay KA, the time delay relay KT and the load L respectively, the relay KA is also connected to the diode RD and the time delay relay KT, and the diode RD is also connected to the time delay relay KT; The power input end of the circuit breaker QF is connected to the positive electrode of the VCC power supply and the moving contacts of a group of normally open contacts of the relay KA, the power output end is connected to the static contacts of a group of normally open contacts of the relay KA and one end of the load L, one end of the control end is connected to one end of the control end of the delay relay KT and the second control signal, and the other end of the control end is connected to the negative electrode of the VCC power supply after being connected to the other end of the control end of the delay relay KT and the other end of the load L.

2. An overcurrent protection anti-sensitivity circuit as claimed in claim 1, characterized in that: One end of the control end of the relay KA is connected to the cathode of the diode RD and the first control signal, and the other end of the control end is connected to the moving contacts of the two groups of normally closed contacts of the delay relay KT and the anode of the diode RD.

3. An overcurrent protection anti-sensitivity circuit as claimed in claim 1, characterized in that: The static contacts of the two groups of normally closed contacts of the time delay relay KT are connected to the load L and then connected to the negative electrode of the VCC power supply.

4. An overcurrent protection anti-sensitivity circuit as claimed in claim 1, characterized in that: The relay KA is an intermediate relay.

5. The overcurrent protection anti-sensitivity circuit according to claim 1, characterized in that: The time delay relay KT is an intermediate relay.

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